I tried to create an USB boot configuration.
However the step 3 - installing syslinus is failing, precisely never ending as stucked at 33% of completion.
I formatted the USB to fat32 using GParted before using it.
Maybe I needed additional dd operation on it ?
The iso is the latest from SuperGrub2Disk.
But I got same problem with other .ISO from the Unetbooting distros lists.
Many thanks for your attention or clue.